1. Field of the Invention
This invention relates to an apparatus and method for receiving a continuous series of rings of hot rolled steel rod emerging from a laying head, and for depositing the rings in an ordered overlapping pattern laying substantially flat on a conveyor for continued transport away from the laying head.
2. Description of the Prior Art
In rod mills, it is common practice to pass hot rolled steel rod through a laying head where it is coiled into a helical series of rings. The rings emerging from the laying head are laid on a conveyor in an overlapping pattern where they are subjected to controlled cooling before being gathered into coils in a reforming chamber at the delivery end of the conveyor.
Rings formed from smaller diameter products, e.g., 5 to 26 mm rods, lie relatively flat on the conveyor, particularly when they are laid at elevated temperatures above about 950xc2x0 C. However, experience has shown that the inherent stiffness of larger diameter products prevents the rings from assuming the desired substantially flat disposition on the conveyor. This is particularly true of the rings formed from the front and tail end portions of a billet length of the product, with the problem being further exacerbated by lower laying temperatures. Thus, for example when processing a 12 mm rod at a laying temperature of about 650xc2x0 C., the leading and trailing rings will exhibit a tendency to resist laying flat and instead will protrude angularly upwardly from the conveyor. These upwardly protruding rings can disrupt orderly coil formation in the reforming chamber.
In U.S. Pat. No. 5,634,607 (Poloni), an attempt is made at dealing with this problem by temporarily blocking the outlet of the laying head in order to collect the leading rings into a densely packed hank which is then abruptly dropped onto the conveyor. A track assembly overlaying the conveyor is then employed to further flatten the rings passing therebeneath.
A drawback with this approach is that the densely packed leading rings of the accumulated hank do not cool at the same rate as the remainder of the overlapping non-concentric rings. This upsets end-to-end metallurgical uniformity of the resulting product.
Another drawback with this approach is that it does not deal effectively with the trailing rings, which also exhibit a tendency to resist laying flat as they are deposited on the conveyor.
An objective of the present invention is to achieve a substantially flat deposit of uniformly distributed rings on the conveyor, from the leading end to the trailing end of a billet length of product.
A companion objective of the present invention is to achieve the aforesaid flat deposit of rings without disturbing the uniformity of ring exposure to coolant application as the rings proceed along the conveyor to the reforming chamber.
In accordance with the present invention, lower portions of the individual rings emerging from the laying head are engaged and directed towards the conveyor at a first rate of travel, and upper portions of the rings are simultaneously engaged and directed towards the conveyor at a different second rate of travel, with the difference between the first and second rates of travel causing the rings to be forcibly toppled onto the conveyor. The simultaneous duel engagement of the upper and lower ring portions produces a controlled deposit on the conveyor in a uniform overlapping pattern.